Probably what you are doing already, give alot of demos so the public can see who you are and have your students do community service. That will boost your rep and if the other guy wants to tear it down, he will either look bad and at least look dubious. Also, these small things that they do usually are on the edge of legal, like bad-mouthing, or outright lies but if it is slander than have the person who you hear it from write it down and sign and date it.
I would also put up your certificates so that anyone looking for the real thing can find them when they visit your dojang. Also pictures of past groups/tournaments are good too. Also compile a sheet of your statistics from results of tournaments, categories and awards, dates, and the event and have it available in the front. List how many black belts you have produced in your brochure.
Improve how your schools looks if that is possible. Neat and clean helps at least with us women and usually we are the "shoppers" in the family.
Usually the better man wins, particularly the one who has been longest in town and most experienced and that would be you. But anytime you want to move your dojang to M'sota, let me know! TW
